The long term objective of this research is to determine what neural systems regulate female sexual behavior and what neural systems regulate male sexual behavior in the rat. Since the neural systems which regulate sexual behavior are themselves influenced by gonadal hormones, the studies here using intracerebral chemical stimulation and perinatal hormone manipulations will also provide insight into the mechanisms by which gonadal hormones affect sexual behavior. The information derived from the experimentation in this proposal will form the basis for investigation into the neural base of sex differences in motivation and behavior.